split Hovers from WithShadow

fixes #4508

OpenRA.Mods.RA/OpenRA.Mods.RA.csproj

@@ -460,6 +460,7 @@
     <Compile Include="UtilityCommands\Extensions.cs" />
     <Compile Include="Lint\CheckMapRules.cs" />
     <Compile Include="Activities\Air\HeliFlyCircle.cs" />
+    <Compile Include="Render\Hovers.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRA.Game\OpenRA.Game.csproj">

OpenRA.Mods.RA/Render/Hovers.cs

@@ -0,0 +1,52 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Graphics;
+using OpenRA.Mods.RA.Activities;
+using OpenRA.Mods.RA.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA.Render
+{
+	[Desc("Changes the visual Z position periodically.")]
+	class HoversInfo : ITraitInfo, Requires<IMoveInfo>
+	{
+		[Desc("Amount of Z axis changes in world units.")]
+		public readonly int OffsetModifier = -43;
+
+		public object Create(ActorInitializer init) { return new Hovers(this, init.self); }
+	}
+
+	class Hovers : IRenderModifier
+	{
+		readonly HoversInfo info;
+		readonly bool aircraft;
+
+		public Hovers(HoversInfo info, Actor self)
+		{
+			this.info = info;
+			aircraft = self.HasTrait<Aircraft>();
+		}
+
+		public IEnumerable<IRenderable> ModifyRender(Actor self, WorldRenderer wr, IEnumerable<IRenderable> r)
+		{
+			if (self.World.Paused)
+				return r;
+
+			var visualOffset = !aircraft || self.CenterPosition.Z > 0 ? (int)Math.Abs((self.ActorID + Game.LocalTick) / 5 % 4 - 1) - 1 : 0;
+			var worldVisualOffset = new WVec(0, 0, info.OffsetModifier * visualOffset);
+
+			return r.Select(a => a.OffsetBy(worldVisualOffset));
+		}
+	}
+}

OpenRA.Mods.RA/Render/WithShadow.cs

@@ -37,13 +37,6 @@ namespace OpenRA.Mods.RA.Render
 
 		public IEnumerable<IRenderable> ModifyRender(Actor self, WorldRenderer wr, IEnumerable<IRenderable> r)
 		{
-			var ios = self.Trait<IOccupySpace>();
-
-			/* rude hack */
-			var flying = ios.CenterPosition.Z > 0;
-			var visualOffset = (ios is Helicopter && flying)
-				? (int)Math.Abs((self.ActorID + Game.LocalTick) / 5 % 4 - 1) - 1 : 0;
-
 			// Contrails shouldn't cast shadows
 			var shadowSprites = r.Where(s => !s.IsDecoration)
 				.Select(a => a.WithPalette(wr.Palette(info.Palette))
@@ -51,11 +44,7 @@ namespace OpenRA.Mods.RA.Render
 				.WithZOffset(a.ZOffset + a.Pos.Z)
 				.AsDecoration());
 
-			var worldVisualOffset = new WVec(0,0,-43*visualOffset);
-			var flyingSprites = !flying ? r :
-				r.Select(a => a.OffsetBy(worldVisualOffset));
-
-			return shadowSprites.Concat(flyingSprites);
+			return shadowSprites.Concat(r);
 		}
 	}
 }